Oxygen radical release from adhering polymorphonuclear leukocytes (PMN) has been implicated as an important feature of many vascular diseases. We developed a technique by which adherence and production of O2 radicals by PMN can be measured simultaneously. The technique combines the conventional nylon fiber assay for measuring adherence of PMN with concurrent scintillation counter measurement of chemiluminescence (CL) to assess O2 radical production by PMN. We found that adherence of PMN to nylon fiber is associated with increases in CL. Moreover, increases in CL appear to be dependent on generation of O2 radicals from PMN since they are not seen with PMN from a patient with chronic granulomatous disease (CGD) or in the presence of O2 radical scavengers, superoxide dismutase, or catalase. Furthermore, agents which increase the adherence of PMN to nylon fiber are associated with increases in CL. Use of this approach may facilitate simultaneous evaluation of adherence and O2 radical generation by PMN.